68 THEORY OF EVOLUTION 



to recessive characters. The next one is 

 dominant. 



A single male appeared with a narrow verti- 

 cal red bar (fig. 31) instead of the broad red 

 oval eye. Bred to wild females the new char- 

 acter was found to dominate, at least to the 

 extent that the eyes of all its offspring were 

 narrower than the normal eye, although not so 

 narrow as the eye of the pure stock. Around 



FIG. 32. Mutant race of fruit fly, called speck. There is a 

 minute black speck at base of wing. 



the bar there is a wide border that cor- 

 responds to the region occupied by the rest of 

 the eye of the wild fly. It lacks however the 

 elements of the eye. It is therefore to be 

 looked upon as a rudimentary organ, which is, 

 so to speak, a by-product of the dominant 

 mutation. 



